A preparation method of surface carboxylated basic copper carbonate for efficiently synthesizing 1,4-butynediol

Abstract

The application discloses a preparation method of surface carboxylated basic copper carbonate for efficiently synthesizing 1,4-butynediol, which comprises the following steps: preparing two equal amounts of copper salt aqueous solution and sodium carbonate aqueous solution, adding one of the copper salt aqueous solution and the sodium carbonate aqueous solution into an aqueous solution containing a small amount of gelatin through a peristaltic pump, controlling the pH of a reaction solution to be 6.0-7.5 and the temperature to be 30-60 DEG C, and then aging by standing, adding the other of the copper salt aqueous solution and the sodium carbonate aqueous solution again according to the foregoing method, and immediately filtering, centrifugally cleaning and drying after the adding is completed, so as to obtain a turquoise green basic copper carbonate powder. The gelatin is used as a structure directing agent, the dropwise adding adsorption-transformation growth-second dropwise adding adsorption reaction process is adopted, the process is simple, high temperature and high pressure are not needed, the batch stability of the product is good, the production efficiency is high, and the industrialized scale-up production is convenient; the prepared basic copper carbonate has carboxyl functional groups on the surface, a regular morphology, a narrow size distribution range and a high bulk density, and exhibits more excellent activity in catalyzing and synthesizing 1,4-butynediol.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial catalysis, and particularly relates to a preparation method of surface carboxylated copper hydroxide carbonate for efficiently synthesizing 1,4-butynediol. BACKGROUND

[0002] 1,4-butynediol is an important chemical product with wide application, which can be used to synthesize butenediol, butanediol, n-butanol, pyrrolidone and a series of important organic products, and further can be used to synthesize plastics, synthetic fibers, artificial leather, medicines, pesticides, solvents and preservatives, and can also be used as a brightener in the electroplating industry. As a catalyst, copper hydroxide carbonate is suitable for the synthesis reaction of 1,4-butynediol prepared from formaldehyde and acetylene, and has the characteristics of good activity and high conversion rate.

[0003] At present, there are various methods for preparing copper hydroxide carbonate, but the copper hydroxide carbonate prepared by the existing methods usually has irregular micro-morphology and structure, has the problems of wide size distribution range and small bulk density, and causes the loading amount of the copper hydroxide carbonate as a catalyst for synthesizing 1,4-butynediol to be small under the same volume. In addition, the copper hydroxide carbonate prepared by the coprecipitation method has low reaction activity and low product yield. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide a preparation method of surface carboxylated copper hydroxide carbonate for efficiently synthesizing 1,4-butynediol.

[0005] In order to achieve the above purpose, the preparation method of surface carboxylated copper hydroxide carbonate provided by the present application comprises the following specific steps:

[0006] Step 1: two equal amounts of copper salt aqueous solution with a mass fraction of 48% to 50% are prepared;

[0007] Step 2: two equal amounts of sodium carbonate aqueous solution with a mass fraction of 20% to 30% are prepared;

[0008] Step 3: water is added to a reaction container, and gelatin is added at the same time, stirring and dissolving to obtain a gelatin aqueous solution with a mass fraction of 1% to 8%, and preheating to 30 to 60 DEG C;

[0009] Step 4: one portion of the copper salt aqueous solution in step 1 and one portion of the sodium carbonate aqueous solution in step 2 are simultaneously added to the preheated gelatin aqueous solution in step 3 by using a peristaltic pump, the dropping speed of the sodium carbonate aqueous solution is controlled to make the pH value of the reaction solution be 6.0 to 7.5, the reaction temperature is controlled to be 30 to 60 DEG C, and the stirring speed is controlled to be 200 to 350 r / min, after the dropping of the copper salt aqueous solution is completed, the reaction is continued for 1 to 2 hours, and the color of the solution changes from blue to emerald green;

[0010] Step 5: Continue to add another portion of the copper salt aqueous solution of Step 1 and another portion of the sodium carbonate aqueous solution of Step 2 to the solution after Step 4, and the reaction pH, temperature, and stirring speed are the same as those of Step 4;

[0011] Step 6: The precipitate obtained in Step 5 is filtered, centrifuged, washed, and dried to obtain a turquoise green surface carboxylated basic copper carbonate powder.

[0012] Preferably, in Step 1, the copper salt is any one of copper nitrate, copper sulfate, or copper chloride.

[0013] Preferably, in Step 1, the copper salt aqueous solution is prepared and in Step 2, the sodium carbonate aqueous solution is prepared, and ultrasonic treatment is performed to make them uniformly dispersed.

[0014] Preferably, in Step 3, the water is preheated to 30°C when preparing the gelatin aqueous solution to promote the dissolution of gelatin. An appropriate amount of gelatin is dissolved and uniformly dispersed in water to form molecular micelles, which will serve as templates for the subsequent spherical heterogeneous nucleation of basic copper carbonate, inhibiting the random homogeneous nucleation process. More importantly, the partial carboxyl functional groups of gelatin will be adsorbed and retained on the surface of basic copper carbonate, thereby enhancing its catalytic activity.

[0015] Preferably, in Step 4, the volume ratio of the gelatin aqueous solution to the copper salt aqueous solution is 1:1 to 3:1. Controlling the pH of the solution within a certain range, either too high or too low, will result in impurities in the final product, producing a color that is not pure, making the size smaller, and causing the bulk density of the product powder to decrease.

[0016] Preferably, in Steps 4 and 5, the duration of the dropwise addition of the copper salt aqueous solution and the sodium carbonate aqueous solution is 0.5 to 1 hour. By controlling the time of dropwise addition, the size of the target product can be effectively controlled to meet the expected requirements.

[0017] Preferably, in Step 6, the solid product is first washed with deionized water and then with ethanol, and the drying temperature is 80 to 120°C. A lower drying temperature requires a longer drying time, reducing production efficiency, and a higher temperature can cause the decomposition of basic copper carbonate, producing copper oxide or copper carbonate impurities.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] 1. In the process for preparing basic copper carbonate, a small amount of gelatin with low price is used as a structure directing agent, and a dropwise adsorption-transformation growth-second dropwise adsorption reaction process is adopted to control the nucleation and growth process of the crystal, so as to induce the crystal to nucleate and grow in a spherical shape, thereby preparing the basic copper carbonate solid microspheres with a diameter of 6-15 μm and a bulk density of 1.3-1.8 g / mL, which have a regular morphology, a narrow size distribution range, a high bulk density, and a surface with carboxyl functional groups and a strong adsorption effect on formaldehyde, are used for the synthesis reaction of 1,4-butynediol with formaldehyde and acetylene as raw materials, have an extremely important promoting effect on the improvement of reaction activity and product yield, and have very high catalytic activity, and can be used as an excellent catalyst in the chemical industry.

[0020] 2. The raw materials used in the application have a wide source and low cost, the target product has high value, the process is simple and easy to operate, high temperature and high pressure are not needed, the product batch stability is good, the production efficiency is high, and the industrialized scale-up production is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the SEM image of the sample prepared in Example 1.

[0022] Figure 2 is the XRD image of the sample prepared in Example 1.

[0023] Figure 3 is the infrared spectrum of the sample prepared in Example 1.

[0024] Figure 4 is the SEM image of the sample prepared in Example 2.

[0025] Figure 5 is the XRD image of the sample prepared in Example 2.

[0026] Figure 6 is the SEM image of the sample prepared in Example 3.

[0027] Figure 7 is the XRD image of the sample prepared in Example 3. DETAILED DESCRIPTION

[0028] The application will be further described in detail below in combination with specific examples and drawings, but the specific examples do not limit the application in any way. Unless otherwise specified, the reagents involved in the specific examples are all commonly used reagents in the art.

[0029] Example 1

[0030] Step 1: At room temperature, two portions of 162 g of copper nitrate trihydrate were weighed and added into two beakers containing 100 mL of water, respectively, stirred and dissolved, and ultrasonically treated for 10 min to prepare two portions of copper nitrate aqueous solution with a mass fraction of 48%;

[0031] Step 2: At room temperature, two portions of 100 g of sodium carbonate were weighed and added into two beakers containing 400 mL of water, respectively, stirred and dissolved, and ultrasonically treated for 12 min to prepare two portions of sodium carbonate aqueous solution with a mass fraction of 20%;

[0032] Step 3: 396 mL of water was added into a 5 L glass reaction kettle, the water was preheated to 30 °C, 4 g of gelatin was weighed and added into the reaction kettle, stirred and dissolved, the stirring speed was set to 200 r / min, a gelatin aqueous solution with a mass fraction of 1% was formed, and was further preheated to 35 °C;

[0033] Step 4: One portion of the copper nitrate aqueous solution of Step 1 and one portion of the sodium carbonate aqueous solution of Step 2 were simultaneously added dropwise into the preheated gelatin aqueous solution of Step 3 by two peristaltic pumps, the pH meter probe was connected to the peristaltic pump corresponding to the sodium carbonate aqueous solution by a programmable controller to automatically control the dropping speed of the sodium carbonate aqueous solution to make the pH value of the reaction solution at 6.2, the reaction temperature was controlled at 35 °C, and the stirring speed was controlled at 250 r / min, after one portion of the copper nitrate aqueous solution was added dropwise for 1 h, the reaction was continued for 2 h, and the solution color slowly changed from blue to turquoise green;

[0034] Step 5: Another portion of the copper nitrate aqueous solution of Step 1 and another portion of the sodium carbonate aqueous solution of Step 2 were continuously added dropwise into the solution of Step 4, the reaction pH, temperature, and stirring speed were the same as those of Step 4, and the dropping process lasted for 1 h;

[0035] Step 6: The precipitate obtained in Step 5 was filtered, washed with deionized water by centrifugation for 3 times, and then washed with ethanol by centrifugation for 3 times, and was placed in an oven at 105 °C for drying for 3 h to obtain a turquoise green surface carboxylated basic copper carbonate powder.

[0036] Figure 1 SEM image of the product of Example 1. As can be seen from the figure, the micro-morphology of the obtained basic copper carbonate is very regular microspheres with a diameter of about 8-12 μm, and the surface is in a granular accumulation state. Figure 2 XRD pattern of the product powder of Example 1. The crystal diffraction pattern of the product is highly matched with the standard card pattern (JCPDS No. 76-0660), and there is no other impurity peak, confirming that the obtained product is basic copper carbonate, which is a monoclinic crystal, and the crystallinity of the crystal is good. Figure 3 Infrared spectrum of the product powder of Example 1. The wave number range is 1500 to 2000 cm -1The peak appearing between 1700 and 1600 cm-1 is the stretching vibration peak of carboxyl, indicating that the obtained basic copper carbonate surface has a certain amount of carboxyl groups, the main reason being that gelatin was used in the preparation process.

[0037] Example 2

[0038] Step 1: At room temperature, two portions of 96 g of anhydrous copper sulfate were weighed and added to two beakers containing 100 mL of water, respectively, stirred and dissolved, and ultrasonically treated for 12 min, to prepare two portions of copper sulfate aqueous solution with a mass fraction of 49%;

[0039] Step 2: At room temperature, two portions of 125 g of sodium carbonate were weighed and added to two beakers containing 375 mL of water, respectively, stirred and dissolved, and ultrasonically treated for 15 min, to prepare two portions of sodium carbonate aqueous solution with a mass fraction of 25%;

[0040] Step 3: 392 mL of water was added to a 5 L glass reaction kettle, the water was preheated to 30℃, 8 g of gelatin was weighed and added to the reaction kettle, stirred and dissolved, the stirring speed was set to 250 r / min, a gelatin aqueous solution with a mass fraction of 2% was formed, and further preheated to 45℃;

[0041] Step 4: One portion of the copper sulfate aqueous solution of step 1 and one portion of the sodium carbonate aqueous solution of step 2 were simultaneously added dropwise to the preheated gelatin aqueous solution of step 3 by two peristaltic pumps, the pH meter probe was connected to the peristaltic pump corresponding to the sodium carbonate aqueous solution by a programmable controller, the dropping speed of the sodium carbonate aqueous solution phase was automatically controlled to make the pH value of the reaction solution 6.5, the reaction temperature was controlled at 45℃, and the stirring speed was controlled at 300 r / min, after one portion of the copper sulfate aqueous solution was added dropwise for 45 min, the reaction was continued for 1.5 h, and the solution color slowly changed from blue to turquoise green;

[0042] Step 5: Another portion of the copper sulfate aqueous solution of step 1 and another portion of the sodium carbonate aqueous solution of step 2 were continuously added dropwise to the solution of step 4, the reaction pH, temperature, and stirring speed were the same as those of step 4, and the dropping process lasted for 45 min;

[0043] Step 6: The precipitate obtained in step 5 was filtered, washed with deionized water by centrifugation for 3 times, then washed with ethanol by centrifugation for 3 times, and placed in an oven at 115℃ for drying for 2 h, to obtain a turquoise green carboxylated basic copper carbonate powder.

[0044] Figure 4 The SEM image of the product of Example 2, basic copper carbonate. As can be seen from the figure, the micro-morphology of the obtained basic copper carbonate is regular micro-spheres with a diameter of about 10-15 μm, and the surface is in a granular accumulation state. Figure 5The XRD pattern of the product of Example 2 is shown in Figure 1. The crystal diffraction pattern of the product matches the standard card pattern (JCPDS No. 76-0660) and no other impurity peaks appear, indicating that the product obtained is copper carbonate hydroxide, which is monoclinic, and the crystallinity of the crystal is high.

[0045] Example 3

[0046] Step 1: At room temperature, two portions of 173 g of copper chloride dihydrate were weighed and added to two beakers containing 100 mL of water, respectively, stirred and dissolved, and ultrasonically treated for 15 min to prepare two portions of copper chloride aqueous solution with a mass fraction of 50%;

[0047] Step 2: At room temperature, two portions of 150 g of sodium carbonate were weighed and added to two beakers containing 350 mL of water, respectively, stirred and dissolved, and ultrasonically treated for 16 min to prepare two portions of sodium carbonate aqueous solution with a mass fraction of 30%;

[0048] Step 3: 388 mL of water was added to a 5 L glass reaction kettle, the water was preheated to 30°C, 12 g of gelatin was weighed and added to the reaction kettle, stirred and dissolved, the stirring speed was set to 300 r / min, a gelatin aqueous solution with a mass fraction of 3% was formed, and further preheated to 50°C;

[0049] Step 4: One portion of the copper chloride aqueous solution of Step 1 and one portion of the sodium carbonate aqueous solution of Step 2 were simultaneously added dropwise to the preheated gelatin aqueous solution of Step 3 by two peristaltic pumps, the pH meter probe was connected to the peristaltic pump corresponding to the sodium carbonate aqueous solution by a programmable controller to automatically control the dropwise addition speed of the sodium carbonate aqueous solution to make the pH value of the reaction solution at 6.8, the reaction temperature was controlled at 60°C, and the stirring speed was controlled at 350 r / min. After the dropwise addition of one portion of the copper chloride aqueous solution was completed for 30 min, the reaction was continued for 1 h, and the solution color slowly changed from blue to turquoise green;

[0050] Step 5: Another portion of the copper chloride aqueous solution of Step 1 and another portion of the sodium carbonate aqueous solution of Step 2 were continuously added dropwise to the solution of Step 4, and the reaction pH, temperature, and stirring speed were the same as those of Step 4, and the dropwise addition process lasted for 30 min.

[0051] Step 6: The precipitate obtained in Step 5 was filtered, washed with deionized water by centrifugation for 3 times, and then washed with ethanol by centrifugation for 3 times, and then placed in an oven at 120°C for drying for 1.5 h to obtain a turquoise green surface carboxylated copper carbonate hydroxide powder.

[0052] Figure 6 The SEM image of the product of Example 3 is shown in Figure 2. As can be seen from the figure, the micro-morphology of the copper carbonate hydroxide obtained is regular micron spheres with a diameter of about 6-12 μm, and the surface is in a granular accumulation state.Figure 7 The XRD pattern of the product copper hydroxide carbonate powder of Example 3 is shown. The crystal diffraction pattern of the product is consistent with the standard card pattern (JCPDS No. 76-0660), and no other impurity peaks are contained, indicating that the product obtained is copper hydroxide carbonate, which is a monoclinic crystal, and the crystallinity of the crystal is good.

[0053] Comparative Example 1

[0054] The gelatin in Example 1 is replaced with water, and the other steps are the same as those in Example 1 to prepare a turquoise copper hydroxide carbonate powder.

[0055] Comparative Example 2

[0056] The gelatin in Example 1 is replaced with an equal amount of polyethylene glycol, and the other steps are the same as those in Example 1 to prepare a turquoise copper hydroxide carbonate powder.

[0057] The copper hydroxide carbonate obtained in Examples 1-3 and Comparative Examples 1-2 is used for catalytic addition reaction to produce 1,4-butynediol from formaldehyde and acetylene. Specifically, 20 g of copper hydroxide carbonate powder and 500 mL of water are added to a reaction kettle to form a catalyst slurry, and formaldehyde and acetylene are introduced into the reaction kettle, respectively. The concentration of formaldehyde is controlled in the range of 45±3%, the concentration of acetylene is controlled in the range of 35±3%, the reaction temperature is controlled at 65±3℃, the pH inside the reaction kettle is controlled at 6.8-7.5, and the pressure at the top of the reaction kettle is controlled at 45±5 kPa. After the test is completed, the residual concentration of formaldehyde is detected by gas chromatography, and the concentration of 1,4-butynediol is detected by liquid chromatography, so as to calculate the yield and selectivity of the target product 1,4-butynediol. The test data are shown in Table 1.

[0058] Table 1

[0059] Sample Formaldehyde conversion / % 1,4-Butynediol selectivity / % 1,4-Butynediol yield / % Example 1 96.6％ 96.5％ 93.2％ Example 2 96.2％ 96.8％ 93.1％ Example 3 96.8％ 96.3％ 93.2％ Comparative Example 1 85.2％ 85.5％ 72.8％ Comparative Example 2 85.6％ 85.3％ 73.0％

[0060] As can be seen from the test results in Table 1, the copper hydroxide carbonate with carboxyl functional groups on the surface prepared by the method of the present application (Examples 1-3) has excellent catalytic activity in the addition reaction of formaldehyde and acetylene. The activity and selectivity of Comparative Example 1 (without using an additive, and the copper hydroxide carbonate obtained has no functional groups on the surface) and Comparative Example 2 (with the addition of polyethylene glycol, and the copper hydroxide carbonate obtained may have a small amount of hydroxyl functional groups on the surface) are both low. The main reason is that the method of the present application uses gelatin, which retains a certain amount of carboxyl functional groups on the surface of the copper hydroxide carbonate, has a strong adsorption effect on the reactant formaldehyde, and thus can improve the reaction activity and product yield.

Claims

1. A method for preparing surface-carboxylated basic copper carbonate for efficient synthesis of 1,4-butynediol, characterized by, The method comprises the following steps: Step 1: prepare two equal amounts of copper salt aqueous solution with a mass fraction of 48-50%; Step 2: prepare two equal amounts of sodium carbonate aqueous solution with a mass fraction of 20-30%; Step 3: add water to a reaction container, and add gelatin while stirring to dissolve, to obtain a gelatin aqueous solution with a mass fraction of 1-8%, and preheat to 30-60°C; Step 4: add one portion of the copper salt aqueous solution of Step 1 and one portion of the sodium carbonate aqueous solution of Step 2 to the preheated gelatin aqueous solution of Step 3 by peristaltic pump, control the dropping speed of the sodium carbonate aqueous solution to make the pH of the reaction solution 6.0-7.5, control the reaction temperature to be 30-60°C and the stirring speed to be 200-350 r / min, after the dropping of the copper salt aqueous solution is completed, continue to react for 1-2 h, and the solution color changes from blue to turquoise green; Step 5: continue to add another portion of the copper salt aqueous solution of Step 1 and another portion of the sodium carbonate aqueous solution of Step 2 to the solution after the reaction of Step 4, and the reaction pH, temperature and stirring speed are the same as those in Step 4; Step 6: filter, centrifugally wash and dry the precipitate obtained in Step 5 to obtain a turquoise green surface carboxylated basic copper carbonate powder.

2. The method for preparing surface-carboxylated basic copper carbonate for efficient synthesis of 1,4-butynediol according to claim 1, characterized in that, In Step 1, the copper salt is any one of copper nitrate, copper sulfate and copper chloride.

3. The method for preparing surface-carboxylated basic copper carbonate for efficient synthesis of 1,4-butynediol according to claim 1, characterized by, In Step 1 for preparing the copper salt aqueous solution and Step 2 for preparing the sodium carbonate aqueous solution, ultrasonic treatment is performed to make them uniformly dispersed.

4. The method for preparing surface-carboxylated basic copper carbonate for efficient synthesis of 1,4-butynediol according to claim 1, characterized by, In Step 3, the water is preheated to 30°C to promote the dissolution of the gelatin.

5. The method for preparing surface-carboxylated basic copper carbonate for efficient synthesis of 1,4-butynediol according to claim 1, characterized by, In Step 4, the volume ratio of the gelatin aqueous solution to the copper salt aqueous solution is 1:1-3:

1.

6. The method for preparing surface-carboxylated basic copper carbonate for efficient synthesis of 1,4-butynediol according to claim 1, characterized by, In Steps 4 and 5, the dropping process of the copper salt aqueous solution and the sodium carbonate aqueous solution lasts for 0.5-1 h.

7. The method for preparing surface-carboxylated basic copper carbonate for efficient synthesis of 1,4-butynediol according to claim 1, characterized by, In Step 6, the solid product is centrifugally washed with deionized water and ethanol in sequence, and the drying temperature is 80-120°C.

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